By using the data of CWave Band Doppler weather radar and the precip itation data from AWS in Taiyuan, a regional snowstorm event occurring in Shanxi on April 11, 2006 was analyzed. The average divergence and vertical velocity of the vertical height layers were calculated quantitatively with the improved tec hnology of EVAD. Their changes in time and space and the corresponding relations hip with this snowstorm were further investigated. The results indicate that the strong updraft always keeping less than 2.5km is the basic dynamical mai n taining mechanism of heavy snowstorms; if anabatic movement appears in whole lower layer and the h eight ofthe strong updraft center is lower and lower along with time accompany ing with strong downdraft in middlehigh layers, then heavy snowstorm will appe ar in 2 hours later there. The intensity of snow is closely related to the divergence and convergence in each height layer within the radar's coverage, and the intensific ation or decrease of the divergence and convergence appears ahead of that of the snow intensity. These results provide some theoretic basis for forecasting the occurrence and disappearance of snowfall and the development of snow intensity.